wcsmbs/btowc.c

   1 /* Copyright (C) 1996-2000,2002,2005 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Ulrich Drepper <drepper@gnu.org>, 1996.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #include <ctype.h>
  21 #include <dlfcn.h>
  22 #include <gconv.h>
  23 #include <stdio.h>
  24 #include <string.h>
  25 #include <wchar.h>
  26 #include <wcsmbsload.h>
  27 #include <limits.h>
  28
  29 #include <sysdep.h>
  30
  31
  32 wint_t
  33 __btowc (c)
  34      int c;
  35 {
  36   const struct gconv_fcts *fcts;
  37
  38   /* If the parameter does not fit into one byte or it is the EOF value
  39      we can give the answer now.  */
  40   if (c < SCHAR_MIN || c > UCHAR_MAX || c == EOF)
  41     return WEOF;
  42
  43   /* We know that only ASCII compatible encodings are used for the
  44      locale and that the wide character encoding is ISO 10646.  */
  45   if (isascii (c))
  46     return (wint_t) c;
  47
  48   /* Get the conversion functions.  */
  49   fcts = get_gconv_fcts (_NL_CURRENT_DATA (LC_CTYPE));
  50   __gconv_btowc_fct btowc_fct = fcts->towc->__btowc_fct;
  51
  52   if (__builtin_expect (fcts->towc_nsteps == 1, 1)
  53       && __builtin_expect (btowc_fct != NULL, 1))
  54     {
  55       /* Use the shortcut function.  */
  56 #ifdef PTR_DEMANGLE
  57       if (fcts->towc->__shlib_handle != NULL)
  58         PTR_DEMANGLE (btowc_fct);
  59 #endif
  60       return DL_CALL_FCT (btowc_fct, (fcts->towc, (unsigned char) c));
  61     }
  62   else
  63     {
  64       /* Fall back to the slow but generic method.  */
  65       wchar_t result;
  66       struct __gconv_step_data data;
  67       unsigned char inbuf[1];
  68       const unsigned char *inptr = inbuf;
  69       size_t dummy;
  70       int status;
  71
  72       /* Tell where we want the result.  */
  73       data.__outbuf = (unsigned char *) &result;
  74       data.__outbufend = data.__outbuf + sizeof (wchar_t);
  75       data.__invocation_counter = 0;
  76       data.__internal_use = 1;
  77       data.__flags = __GCONV_IS_LAST;
  78       data.__statep = &data.__state;
  79       data.__trans = NULL;
  80
  81       /* Make sure we start in the initial state.  */
  82       memset (&data.__state, '\0', sizeof (mbstate_t));
  83
  84       /* Create the input string.  */
  85       inbuf[0] = c;
  86
  87       __gconv_fct fct = fcts->towc->__fct;
  88 #ifdef PTR_DEMANGLE
  89       if (fcts->towc->__shlib_handle != NULL)
  90         PTR_DEMANGLE (fct);
  91 #endif
  92       status = DL_CALL_FCT (fct, (fcts->towc, &data, &inptr, inptr + 1,
  93                                   NULL, &dummy, 0, 1));
  94
  95       if (status != __GCONV_OK && status != __GCONV_FULL_OUTPUT
  96           && status != __GCONV_EMPTY_INPUT)
  97         /* The conversion failed.  */
  98         result = WEOF;
  99
 100       return result;
 101     }
 102 }
 103 weak_alias (__btowc, btowc)